serpentinisation

Serpentinisation is a geological process that involves the alteration of mafic and ultramafic rocks, primarily composed of olivine and pyroxene, into serpentine minerals. This process occurs through the reaction of these rocks with water, typically at low temperatures and pressures. Serpentinisation is significant in the context of geology, geochemistry, and astrobiology.

The process begins when water, often in the form of seawater or hydrothermal fluids, infiltrates fractures and pores within the rock. This water reacts with the iron and magnesium-rich minerals, leading to the formation of serpentine minerals such as lizardite and chrysotile. This reaction is exothermic, meaning it releases heat, which can further drive the process.

Serpentinisation has several important implications. It can lead to the formation of economically valuable minerals, such as asbestos and chromium. It also plays a role in the global water cycle by releasing hydrogen gas, which can be a source of energy for certain microorganisms. Additionally, serpentinisation can influence the physical properties of rocks, such as their density and strength, and can create habitats for unique ecosystems.

In the context of astrobiology, serpentinisation is of particular interest because it can provide the necessary chemical energy for the emergence and maintenance of life. The hydrogen gas produced during serpentinisation can be used by certain microorganisms as an energy source, and the process can create environments that are conducive to the development of life.